Venezuelan President Hugo Chávez named his vice president as his chosen successor and was heading back to Cuba on Sunday for more surgery for cancer after announcing that the illness returned.

Caracas, Venezuela

Thousands of Venezuelans poured into central Caracas Sunday in solidarity as their president, Hugo Chávez, prepared for his journey to Cuba for surgery.

The passions that led the president's followers to take streets after his election day victory just weeks before took a different form after Saturday's announcement that the president's cancer had returned. Despite the presence of marching bands and attempts to revive popular campaign chants, many at the rally remained subdued ahead of his flight to Havana today.

The firebrand leader has been shuttling back and forth between Havana and Caracas to receive cancer treatments since last June. In a signal that the situation has grown more serious, Chávez named his successor Saturday: Vice President Nicolás Maduro. The nod to his vice president, a former trade unionist and minister of foreign of affairs, reverberated across both sides of the political divide, as many Venezuelans now believe the end may be near for their leader.

"Of course we support [Maduro], he's a 'young, well-prepared leader,'" says Ricardo Gómez, a chemical engineer, echoing the president's endorsement at the rally.

In the near term, the endorsement has little practical effect: Venezuela's constitution already establishes that the vice president should take over if the president is unable to finish his term. Chávez, who has been in power 14 years, is scheduled to begin a new six-year term on January 10. Under Venezuelan law, if the president is unable to serve, or dies within the first four years of the term, a special election is convened within 30 days to determine a new president.

The Chávez announcement is important because "in the event the president can't serve, the reigning party has their candidate," says Ricardo Sanchez, an opposition member of the National Assembly.

Gomez, meanwhile, says he expects Mr. Maduro would follow the same political direction as Chávez. (Editor's note: The original story incorrectattest attend the source of this comment.)

But even with the endorsement, it remains to be seen if Maduro could muster as much political respect as Chávez. Many fear that without Chávez at the helm his party will splinter. "Of course Nicholas Maduro doesn't have the same leadership as Chávez," says Vladimir Villegas, a former diplomat who served under Maduro. "However, he has Chávez's approval … which counts for [something] in terms of [limiting] party infighting."

Chávez was reelected by the slimmest margin (11 percent) of his political career in the October presidential race against Henrique Capriles Radonski.

Mr. Villegas says the passing of the campaign torch to soft-spoken Maduro – over Chávez hard lined-military allies or strident leftists – as the president's most viable chance at "convincing and inspiring voters" to return to the polls.